1. Field of the Invention
This invention relates to bushes, and more particularly to a bush for installation in apertured work of easily marred or crushed material to receive a bolt or similar headed fastening device, and whereby the bolt can be prevented from damaging the work.
2. Background of the Related Art
Honeycomb structural materials and composite materials such as plastics material having reinforcement fibers of carbon or glass, particularly in the form of sheets, are used extensively where their light-weight properties and high-tensile strength are advantageous. However, such materials are easily marred or crushed, or otherwise subjected to physical damage, resulting in significant impairment of their desirable properties. Such damage can occur when work made of such materials is assembled and fastened together using fasteners, such as bolts or the like, having a head of small bearing area which bears on a surface of the material adjacent to a hole through which a shank of the fastener passes. Thus, the head of the fastener may crush the material, or may abrade, tear, or otherwise mar the surface of the material, to the considerable detriment of its properties. Furthermore, the shank of the fastener, having a small bearing area, may also damage the material around the hole unless the hole is sleeved or bushed in order to reinforce the material or increase its bearing area.
We have now devised a bush for installation in an aperture in work which may be easily marred or crushed, and which will afford protection to the work against damage by a bolt used to fasten the work to another structure.